Manufacture of isopropyl chloride



Patented Oct. 28, 1947 MANUFACTURE OF ISOPROPYL CHLORIDE Frank '0. Holmes, Baton Rouge, La., assignor to Ethyl Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application October 22, 1945,

' Serial N or 623,857

2 Claims. (Cl. 260-663) This invention relates to a catalysed hydrochlorination of propylene. Many hydrochlorination catalysts are known but they are not sufficiently selective in .their action so as to vo d. the hydrochlorination of ethylene along with the de-- sired hydrochlorination of propylene.

vention, hydrogen chloride is mixed with pure propylene, the hydrogen chloride/propylene mole One practical problem is the purifying of gaseous feed streams containing both ethylene and propylene. Such streams are obtainable from cracking furnaces or as by-products in dehydrogenation processes. The propylene is a disadvantageous, reactive impurity when such gases are processed to make derivatives of ethylene. I

have discovered that granular anhydrous calcium 1 sulfate is a selective catalyst for producing a re-. action between hydrogen chloride and propylene to form isopropyl chloride, without catalyzing the hydrochlorination of co-present ethylene. The isopropyl chloride so formed may be easily removed by cooling the gas and condensing the isopropyl chloride. The isopropyl chloride may also be left in the gas, as it does not exhibit the disadvantages found when free propylene is present. I,

A granular anhydrous calcium sulfate is on the market under the trade name Drierite" and it is made by the process described in U. S. Patent No. 1,887,349 to William A. Hammond. However, I find thatthls patent names maximum temperatures of about 300', C. Drierite, which has been heatedto 400* c. for three .hours, has just as good catalytic properties in my process as Drierite which has been heated to the lower temperatures named in the patent.

As is usual in gas phase catalysis, the lump size of the catalyst will be selected to provide adequate contact of the reacting gases, without a greater degree of propylene conversion. Subratio being 1.05:1. The mixed gases are passed into a reactor maintained at 200 C. and operating at substantially atmospheric pressure. Ap-

proximately 90% of the propylene reacts to produce isopropyl chloride. Such a process has been continuously operated for over-100 hr. without any measureable decrease in yield, or cracking or polymerization of the hydrocarbon. A greater excess of hydrogen chloride'is accompanied by stantially the same results were obtained at room temperature and 100 pounds pressure.

There is nothing critical in the reaction in temperature, pressure or mole ratio. No advanbeing so fine as to require high pressures to force 1 the gases through the catalyst bed.

In one method of carrying out my invention with an ethylene stream containing by volume 3% propylene, I add sufiicient hydrogen chloride gas to react with all the ethylene andpropylene.

tage has been found in using reaction temperatures substantially above 200 C. The reaction has been obtained at room temperature and without elevating the pressure. At reaction temperatures substantially below 200 C. I prefer to increase the pressure and have obtained good reactions at 35 C. and 150 C. at 100 pounds pres-' The catalyst may become deactivated. The

cause of deactivation is not understood, but it is believed that small amounts of adsorbed impurities on the surface of the calcium sulfate prevent the catalysis in this reaction. The catalyst is reactivated by heating it to above 100 C 'and preferably to about 200 C.

I I claim:

1. The process of making isopropyl chloride which comprises bringing gaseous hydrogen chloride and propylene into contact with granupropylene in a propylene-ethylene mixture which comprises bringing the mixture and hydrogen chloride'into contact with granular anhydrous v The following references are of record in the file of this patent:

YUIJIITED s'rA'rEs PA'I'EN'rs gen chloride to react with all the ethylene. The Number Name Date excess of hydrogen chloride is used to have it in 1,591,151 Wibaut July 6, 1926 the feed stream for further hydrochlorination 1,637,972 Suida Aug. 2, 1927 following the hydrochlorination of propylene. 2,031,228 Reilly Feb. 18, 1936 In another method of carrying out the in- 2,328,275 Heard Aug. 31, 1943 

